Changes in the dentoalveolar complex during adolescence : a lifecourse study

Abstract

Assessment of the dentoalveolar complex, and particularly changes in it during adolescence is of key importance in the diagnosis of malocclusion, orthodontic treatment planning; and ultimately may influence the outcome of orthodontic intervention. To date, there has been limited studies of changes in the dentoalveolar complex during adolescence, particularly among community/population-based samples. With advances in technologies there is a growing interest in three-dimensional (3D) analyses of the dentoalveolar complex; although studies of 3D changes are scant. The current study aimed to comprehensively investigate dentoalveolar development during adolescence and its association with Angle’s Classification of Malocclusion. A lifecourse epidemiological study of 3D changes of the dentoalveolar complex during adolescence was undertaken among a population sample in Hong Kong SAR, People’s Republic of China. Digital models were obtained at age 12, 15 and 18; and analysed for changes of conventional dentoalveolar linear, angular, and volume features over time. Associations between changes in dentoalveolar attributes during adolescence and Angle’s Classification of Malocclusion were examined. In addition, changes in arch form (via cluster and geometric morphometric analyses) were undertaken, and changes in individual tooth position during adolescence were determined. Over 600 digital models were obtained during adolescence (at age, 12, 15 and 18) and 272 landmarks were identified on each model. The reliability and validity of assessments were confirmed. There were significant changes during adolescence of linear dentoalveolar features: arch widths (p<0.01); alveolar widths (p<0.01), arch depths (p<0.001); arch lengths (p<0.001); arch irregularities (p<0.001); Curve of Spee depths (p<0.001); and inter arch relationship (p<0.001). There were also significant changes during adolescence of angular dentoalveolar features: tooth angulations (p<0.05), inclinations (p<0.05) and rotations (p<0.05). Furthermore, there were significant changes in palatal volume during adolescence (p<0.001). There was no significant change in Angle’s Classification of Malocclusion during adolescence (p>0.05). For the most part, no significant associations between changes in dentoalveolar features and Angle’s Classification of Malocclusion were observed (p>0.05). During adolescence there were significant changes in arch form as identified from cluster analyses (p<0.001) and Procrustes analyses (p<0.001). Moreover, during adolescence significant changes in the position of most teeth were observed in 3D space (p<0.05). In conclusion, significant changes in dentoalveolar features occurs during adolescence: linear, angular and volume changes but no significant changes in Angle’s Classification of Malocclusion were observed. Changes in dentoalveolar features during adolescence were infrequently associated with Angle’s Classification of Malocclusion. Furthermore, significant changes in arch form and in the position of teeth during adolescence occurred. These findings have important implications and can inform orthodontic diagnosis, orthodontic treatment and the prognosis of orthodontic care (or prognosis as a result of a lack of orthodontic care); particular among Southern Chinese, and potentially beyond.